function isIdCard(cardNum) {
  if (cardNum == "") return null
  if (!/(^\d{15}$)|(^\d{17}(\d|X|x)$)/.test(cardNum)) {
    return false
  }
  //身份证城市
  var aCity = {
    11: "北京",
    12: "天津",
    13: "河北",
    14: "山西",
    15: "内蒙古",
    21: "辽宁",
    22: "吉林",
    23: "黑龙江",
    31: "上海",
    32: "江苏",
    33: "浙江",
    34: "安徽",
    35: "福建",
    36: "江西",
    37: "山东",
    41: "河南",
    42: "湖北",
    43: "湖南",
    44: "广东",
    45: "广西",
    46: "海南",
    50: "重庆",
    51: "四川",
    52: "贵州",
    53: "云南",
    54: "西藏",
    61: "陕西",
    62: "甘肃",
    63: "青海",
    64: "宁夏",
    65: "新疆",
    71: "台湾",
    81: "香港",
    82: "澳门",
    91: "国外"
  };
  if (!aCity[parseInt(cardNum.substr(0, 2))]) {
    return false
  }

  // 出生日期验证
  var sBirthday = (cardNum.substr(6, 4) + "-" + Number(cardNum.substr(10, 2)) + "-" +
    Number(cardNum.substr(12, 2))).replace(/-/g, "/"),
    d = new Date(sBirthday)
  if (sBirthday != (d.getFullYear() + "/" + (d.getMonth() + 1) + "/" + d.getDate())) {
    return false
  }

  // 身份证号码校验
  var sum = 0,
    weights = [7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2],
    codes = "10X98765432"
  for (var i = 0; i < cardNum.length - 1; i++) {
    sum += cardNum[i] * weights[i];
  }
  var last = codes[sum % 11]; //计算出来的最后一位身份证号码
  if (cardNum[cardNum.length - 1] != last) {
    return false
  }

  return true

}

export {
  isIdCard
}